Evidence and theoretical considerations point towards hormonal mechanisms in ovarian carcinogenesis. Because of the widespread use of hormones for prevention and treatment of wide variety of diseases (e.g. cancer, cardiovascular disease and osteoporosis) it is critical to understand the effects of hormones on the development of ovarian cancer in order to predict the safety of hormone interventions and to develop new methods of prevention. We hypothesize that androgens and insulin-like growth factor, are associated with the development of ovarian cancer and could be potential targets for prevention interventions. A prospective study will be conducted using the efficiency of a nested case control design, to evaluate the association between circulating components of the insulin growth factor (IGF) axis, endogenous androgens and the subsequent development of ovarian cancer. Cases and controls will be selected from the Washington County, MD cohort studies, CLUE I and CLUE II. All participants have blood available prior to the time of diagnosis of cancer. 86 women from these cohorts have developed ovarian cancer and are eligible for the study. Each case will be matched to two controls by age, race, cohort participation, menstrual status (including time since last menstrual period), and date of blood draw. This study will contribute to the understanding of the etiology of ovarian cancer. Designs of future hormonal chemopreventive intervention need to be based on a clearer understanding of the hormonal influences underlying cancer so that potential risks and benefits of existing and new interventions can be determined.